title: Balance ability and postural stability among patients with painful shoulder disorders and healthy controls.
abstract: BACKGROUND
  In therapeutic settings, patients with shoulder pain often exhibit deficient coordinative abilities in their trunk and lower extremities. The aim of the study was to investigate 1) if there is a connection between shoulder pain and deficits in balance ability and postural stability, 2) if pain intensity is related to balance ability and postural stability, and 3) if there is a connection between body mass index (BMI) and balance ability and postural stability.
  
  
  METHODS
  In this case-control study, patients (n = 40) with pathological shoulder pain (> 4 months) were matched with a healthy controls (n = 40) and were compared with regard to their balance ability and postural stability. Outcome parameters were postural stability, balance ability and symmetry index which were measured using the S3-Check system. In addition, the influence of shoulder pain intensity and BMI on the outcome parameters was analysed.
  
  
  RESULTS
  Patients with shoulder pain showed significantly worse results in measurements of postural stability right/left (p < 0.01) and front/back (p < 0.01) as well as balance ability right/left (p = 0.01) and front/back (p < 0.01) compared to healthy controls. There were no significant group differences with regard to symmetry index. However, there was a significant (p < 0.01) symmetry shift towards the affected side within the shoulder pain group. There was no correlation between pain intensity and measurements of balance ability or postural stability. Likewise, no correlation between BMI and deficiencies in balance ability and postural stability was established.
  
  
  CONCLUSIONS
  Patients with pathological shoulder pain (> 4 months) have deficiencies in balance ability and postural stability; however the underlying mechanisms for this remain unclear. Neither pain intensity nor BMI influenced the outcome parameters. Patients with shoulder pain shift their weight to the affected side. Further research is needed to determine if balance training can improve rehabilitation results in patients with shoulder pathologies.
authors.affiliation: ZHAW Zurich University of Applied Sciences, Technikumstrasse 71, Winterthur 8401, Switzerland. luom@zhaw.ch.
authors.forename: Tobias
authors.initials: T
authors.lastname: Baierle
authors.forename: Thilo
authors.initials: T
authors.lastname: Kromer
authors.forename: Carmen
authors.initials: C
authors.lastname: Petermann
authors.forename: Petra
authors.initials: P
authors.lastname: Magosch
authors.forename: Hannu
authors.initials: H
authors.lastname: Luomajoki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010808:Physical Examination; D004856:Postural Balance; D011187:Posture; D012678:Sensation Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D012782:Shoulder / Q000503:physiopathology*; D020069:Shoulder Pain / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology